Carbon dots as fluorescent sensor for detection of explosive nitrocompounds. (September 2016)

• Record Type: Journal Article
• Authors: Campos, Bruno B.; Contreras-Cáceres, Rafael; Bandosz, Teresa J.; Jiménez-Jiménez, José; Rodríguez-Castellón, Enrique; Esteves da Silva, Joaquim C.G.; Algarra, Manuel
• Is Part Of: Carbon. Volume 106(2016)
• Page Start: 171
• Page End: 178
• Publication Date: 2016-09
• Subjects: Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2016.05.030
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: Highly and stable fluorescent carbon dots (CQDs), with λex /λem = 350/465 nm were obtained using a strong acid oxidation of activated carbon in aqueous suspension. The nanoparticles had a mean size of 12 nm and quantum yield of 3.94%. After functionalization with amine groups by PAMAM-NH2 dendrimer (CQDs@PAMAM-NH2 ), the size of particles increased and aggregates of 65 nm were formed. Quantum yield also increased to 6.33%. CQDs were characterized by various analytical techniques including ATR-FTIR, Raman, XPS and fluorescence spectroscopies. The prepared CQDs@PAMAM-NH2 were used as fluorescent ratiometric nanosensor of 4-chloro-2, 6-dinitroaniline, which is a constituent of explosives. As a result of interactions, the fluorescence at 465 nm was quenched. Moreover, a new band at 507 nm emerged and it is linked to a charge transfer and the formation of a Meisenheimer complex. A ratio of fluorescence intensities at 465 and 507 nm (I465 /I507 ) is used for a ratiometric fluorescence sensing. A linear detection ranges from 1.0 × 10 −5 to 6.0 × 10 −4 M with a detection limit of 2 μM and accuracy of 0.85% as standard relative deviation (RSD, n = 10). The detection accuracy in the presence of other nitrocompounds was 2.80% as RSD.